The state's highest court, in a 5-2 decision, said the denial of benefits to same-sex partners of public employees was covered by a 2004 amendment to the state constitution that defined marriage as the union of one man and one woman, the Detroit Free Press reported.

The court said language in the amendment prohibiting recognition of other unions "for any purpose" includes providing of benefits to gay and lesbian partners of those who work for public employers, the newspaper said.

Ave Maria Law School Professor Patrick Gillen, who co-wrote the amendment, called the decision "a vindication of the will of people in enacting the marriage amendment."

However, Jessie Olson, an attorney who for those seeking the benefits extension, called it a setback for civil rights.

"We are the worst of the worst of the worst when it comes to civil rights for same sex couples," Olson said.

Olson said appealing to federal court carried the risk of affecting all states if proponents lose.

"The only alternative may be just leaving," he told the Free Press, "joining the exodus of people who are just getting out of Michigan."